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(No Model.) 2 Sheets-Sheet 1. J. P. GILLILAND. TELEPHONE SWITUHBOARD..

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J. P. GILLILAN'D TELEPHONE SWITGHBO AED. No. 542,249. Patented July 9,1895..

l i Q h zvwneooco T ywewlio z OM M 315. toz wz UNITED STATES PATENTOFFICE.

' JAMES F. GILLILAND, OF ADRIAN, MICHIGAN, ASSIGN OR TO THE GILLILANDELECTRIC COMPANY, OF SAME PLACE.

TELEPHONE-SWITCHBOARD.

SPECIFICATION forming partof Letters Patent No. 542,249, dated July 9,1895. Application filed October 26, 1894- Serial No. 527,008. (Nomodel.)

To all whom it may concern:

Be it known that 1, JAMES F. GILLILAND, a citizen of the United States,residing at Adrian, in the county of Lenawee and State of Michigamhaveinvented a certain new and useful Improvement in Telephone-Switchboards, of which the following is a specification.

The object I have in view is to produce a telephone-switchboardespecially designed for metallic'circuits, which will be simple andcheap in construction and efficient in opera tion.

In carrying out my invention I terminate the telephone-lines at theexchange in movable plugs, at which the lines are normally closed. Theswitchboard is provided with a number of pairs ofplates running parallelto each other and insulated from each other and unprovided with anycircuit-connections, the connections between two telephone-linesbeingproduced by pushing the plugs of the lines over the plates of thesame pair. This operation opens the lines at the plugs and connects themtogether.

The invention also involves a provision for cutting out theannunciator-drops by the movement of the annunciator-shields themselves,and for utilizing this same device to ring a night-bell, in the case ofsmall exchanges.

In the accompanying drawings, forming a part hereof, Figure 1 is afront'elevation of one section of the switchboard, showing broken awaythe edge of an adjoining section. Fig. 2 is a side elevation of theswitchboard. Fig. 3 is a sectional View showing the circuit,-counections with one drop and one plug. Fig. 4: is a sectional Viewshowing one plug pushed over a pair of connector-plates; and Fig. 5 is aperspective view, on a larger scale, of one of the plugs and a pair ofconnector-plates.

In my improved switchboard the metallic telephone-lines terminate eachin a plug A, having. closed spring-jaws a a, at which the telephone-lineis normally closed. These plugs are connected with flexible cords B,carrying each a pair of conductors running to binding-screws, at whichthe telephone-line for the particular plug terminates. The plugsnormally rest in openings formed in the top of a rack O, which ispreferably constructed in steps, as shown, for convenience in hand-'ling the plugs. Beneath the rack the slack of the flexible cords istaken up by weights or otherwise. Rising above the rack O is a frame D,the side uprights of which are connected by a number of pairs ofinsulated platesE F, and above these plates the top of the frame isoccupied by the annunciator-drops G.

As illustrated in the drawings, a switchboard or section for fiftytelephone-lines and having, consequently, fifty drops will also beprovided with five-of the pairs of plates E F but this number may be ofcourseincreased. A line wire 1-2 for each telephone passes through theannunciator-magnets for the particular line, and also through the plug Afor that line, as illustrated in Fig. 3. The shield of each annunciatorhas its rod b arranged to drop in falling upon a spring 0, depressingthe same and causing it to make contact with the plate at. The spring 0.and plate d are connected by wires 3 4 with the wires 1 2 of thetelephone-line outside of the annunciatordrop, so as to shunt the dropwhen the annunciator-shi'eld falls. When the annunciator-shield israised, so that its weight does not rest on the spring a, that springrises and, leaving the plate (1, breaks the shunt. The plates 0 d arealso connected with a local circuit 5 6, in which are located avibrating bell II, operated by a local battery I and provided with aswitch K, by means of which the local circuit can be opened. It theswitch K is closed, the dropping of the annunciator will not only shuntthe annunciator-magnet, but will start-the bell 'I-I ringing, thuscalling attention to the fact that'a call has been received. This devicewill be used as a nightbell in small ofiices. The local circuit may bekept permanently open during the daytime by means of the switch K.

The pairs of plates E F'have no circuit connections whatever, exceptthat I design to con nect the plates of the lowermost pairwith the usualgenerator L, supplying an alternating current for calling subscribers.This connection is indicated by the wires 7 8. If the exchange isprovided with more than one section of this switchboard, the pairs ofplates of the different sections may be connected together by plugs, asshown in Fig. 1. The

plugs for this purpose will be precisely like 5 the plugs A, except theywill not have any flexible cord connected with them, the springs a a.being wide enough to overlap the adjoining ends of the pairs of plates.

If a subscriber calls, the shield of the corresponding annunciator willdrop, shunting out the annunciator-magnet and ringing the hell it thelatter is connected. The operator then takes the plug of the particularsubscribers line and pushes it over one pair of plates, at the same timetaking the plug of his own telephone and pushing it over the same pairof plates. After ascertaining the number of the telephone with which thesubscriber calling wishes to be connected, the operator will take theplug of the second line and push it over the connector-plates of thefirst pair, which are connected with the generator for calling. Thiscalls up the person wanted, and when the operator thinks the call hasbeen continued a suflicient length of time he removes the plug of thesecond line from the first pair of connector-plates and pushes it overthe pair of plates with which the first line is already connected.Having put the parties into communication, the operator may disconnecthis own telephone by pulling the plug from the strip, or he may leavehis plug connected with the same strip. If the operator removes his plugfrom the connector-strips he can raise one of the drops connected withthe two lines in communication, so that if either or both personstalking rings olt at the end of the conversation the annunciator willdrop and notify the exchange. In case a long line is in use and it isdesirable to have both drops out of circuit, the shields can be leftdown, so as to shunt the magnets, and the operator will have to dependupon his own telephone to find out when the parties are through talking.The

instant the plug is removed from the pair of connector-strips thesprings aa come together and close the particular line.

If it is desired to use the same pair of connector-strips on two boardsfor making different connections the plug connecting the ends of thestrips between the boards may be removed.

It is obvious that many changes in the details of the construction ofthe parts may be made without departing from the spirit of my invention.

What I claim is 1. In a telephone switclyboard, the combination of linesterminating in movable plugs at which they are normally closed, of apair or pairs of insulated connector plates, having no circuitconnections, and adapted to engage withthe plugs and connect the linestogether, substantially as set forth.

2. In a telephone switch-board, the combination with telephone lines, ofmovable plugs having normally closed spring contacts connected with thetelephone lines, of a series of pairs of flat connector plates,insulated from each other and adapted to have the spring contacts of theplugs pushed over them, substantially as set forth.

3. In a telephone switch-board, the combination with telephone linesterminating at movable plugs at which the lines are normally closed, ofa pair of connector plates, insulated from each other, and connectedwith the calling generator, and other similar pairs of plates, withoutany circuit connec tions, such plates being adapted to engage with theplug contacts so as to open them and connect them with any other circuitconnected with the same pair of plates, substantially as set forth.

This specification signed and witnessed this 22d day of October, 189-1.

JAMES F. GILLILAND. Witnesses:

HENRY 0. SMITH, CLARK E. BALDWIN.

